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A183547
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Number of n X 2 0..2 arrays with each element equal to either the maximum or the minimum of its horizontal and vertical neighbors.
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1
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3, 15, 71, 299, 1325, 5845, 25785, 113841, 502523, 2218399, 9793287, 43233099, 190855613, 842545925, 3719480233, 16419916497, 72486917979, 319998782959, 1412657953559, 6236281512443, 27530519336653, 121535484480133
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 5*a(n-1) - 3*a(n-2) + 4*a(n-3) - 9*a(n-4) - 13*a(n-6) + 8*a(n-7) + 4*a(n-8) + 7*a(n-9) + 2*a(n-10).
Empirical g.f.: x*(3 + 5*x^2 - 23*x^3 + 10*x^4 - 32*x^5 + 17*x^6 + 13*x^7 + 9*x^8 + 10*x^9) / (1 - 5*x + 3*x^2 - 4*x^3 + 9*x^4 + 13*x^6 - 8*x^7 - 4*x^8 - 7*x^9 - 2*x^10). - Colin Barker, Mar 29 2018
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EXAMPLE
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Some solutions for 3 X 2:
..0..0....2..2....1..1....2..2....1..1....0..0....2..1....1..1....0..0....2..2
..1..0....1..2....2..1....0..0....0..1....1..1....2..1....0..0....2..0....0..2
..1..1....1..1....2..1....1..1....0..1....1..1....2..1....1..1....2..0....0..2
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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